February 6, 1950
Septimus is crouched down, holding his wife, Cedrella's hand. She has been in labor for hours. Septimus insisted to her that they go to a muggle hospital to give birth to their first son but she refused. So, there they were, at their own home, the burrow they called it, with no one but the midwife to help bring their little one into the world. Cedrella's family had not even bothered to speak to her since the announcement of her engagement to Septimus. They were strong believers in pure-blood supremacy and Septimus was born to muggle parents. Refusing to give up love, Cedrella became another burned out face on the Black family tree.
None of this mattered now. Septimus was determined to give Cedrella a life filled with every happiness he could give her. And this was one of those gifts: a beautiful, screaming, red-headed baby boy. "Arthur," said Cedrella as the midwife handed the boy to her. Septimus moved in closer. He stared at his son with the fire engine red hair and wondered how such a beautiful being could be his.
Summer of 1955
Arthur is now 5 years old. He is shy and often plays by himself. Cedrella and Septimus have been fighting over where to send Arthur to school before he got his Hogwarts letter and Arthur was always able to listen to them fight from his bedroom. Cedrella wants to home school Arthur, now a big brother to two more boys. Septimus thinks that Arthur should experience life without magic so he an appreciate it more like he did coming from a muggle family. Out of nowhere, Cedrella shouts, "NO CHILD OF MINE WILL EVER BE FORCED TO INTERACT WITH THOSE PEOPLE!"
The look of shock on Septimus' face said it all. He felt as if his heart had been ripped out of his chest. "Those people," she said. He thought she had gotten over the fact that his parents were muggles but clearly he was wrong. How could he love someone who did not accept who he was? He came to the conclusion that he couldn't and Cedrella agreed with him. She missed her family. As horrible as they were, they were her blood and she knew she belonged with them. But they would never accept Arthur. He was only half-blood and would never be treated like a member of the family. Septimus and Cedrella agreed that Septimus would take Arthur and his brothers away and would neither of them would ever see or hear from Cedrella again.
Arthur's 10th Birthday
Arthur had a great relationship with his father. Ever since his mother left, his father did everything he could to make sure Arthur was well fed and had everything he wanted. Being a single father was rough for Septimus. He worked so much he rarely got to see his children. He was determined to be a good provide for the boys. Septimus always made the best of every moment he had, especially with his eldest, Arthur, with whom he had a special bond.
But today was Arthur's tenth birthday. He couldn't wait to get home from school to see what his dad got him. Septimus always got Arthur the best gifts! He got Arthur a new toy or trinket that the muggles used. A new one every year. Cedrella had hated that Septimus did this but he was determined to pass on his culture to his son. Arthur had a special shelf with 9 of these muggle toys on them and had already cleared out a spot for the 10th. Septimus had so little time on his hands, he never really got to show Arthur how to use the toys, but Arthur was always curious about them.
It had come time for Arthur to open his gift from his father. Septimus handed him a little box with a bow on it. He tore open the box to reveal a shiny, rubber duck. Arthur's eyes grew wide with fascination. He had never seen a muggle toy so colorful as this one was. A big smile came over his face and Septimus knew he had done well. Arthur ran to his room and placed the duck in its designated spot on his shelf, right next to the rest of his father's gifts.
September 1, 1956, 10:45
It was finally time for Arthur to begin his magical education. He, Septimus and his two brothers had just made the cross onto platform 9 3/4. The boys stood in awe of the huge train that was the Hogwart's Express. It was time to say their goodbyes. Arthur hugged his brothers and they ran off so he and Septimus could have a moment alone. "I am so proud of you, son. You'll do great at Hogwarts," he said. A wave of sadness swept over Arthur and his eyes began to water. "Thanks dad. I'll write to you as much as I can," replied Arthur. Little did Septimus know that his son brought all 11 of his muggle toys to Hogwarts with him. It is here where Arthur's true infatuation with muggles began.
Arthur would graduate from Hogwarts and soon after marry Molly Prewitt wtih whom he would have sons Bill, Charlie, Percy, Fred, George, Ron and daughter Ginny. Arthur would work in the Ministry of Magic in the Misuse of Muggle Artifacts department. He still, to this day, does not know the function of a rubber duck.
Source: Harry Potter Wiki
HP Wiki was only used for background information such as parent names and date of birth. Other than that this is a story I created!